1. Field of the Invention
This invention relates to key operated switches and more particularly to anti-static switch locks and methods for assembly thereof.
2. Description of the Prior Art
Anti-static switch locks occurring in the prior art are exemplified by U.S. Pat. No. 4,009,357 issued to Naylor, Feb. 22, 1975. Locks of this type are comprised of a metallic barrel which houses a rotatable, key operated plug. Affixed to the end of the plug is a shaft which, in turn, has on its end a rotor. The rotor, housed within a terminal assembly, connects the various terminals of a terminal assembly upon rotation of the plug. Holding the terminal assembly to the barrel is a non-conductive adapter having a pair of legs to engage and hold the adaptor to the barrel. A similar pair of legs engage and hold the terminal assembly to the adaptor.
The switch locks of the aforementioned type are subject to the problem of disengagement of the adapter from the barrel resulting in disassembly of the lock. Furthermore, these switch locks do not have a means whereby the plug and rotor may be biased toward a specific position.
An improvement over switch locks exemplified by U.S. Pat. No. 4,009,357 is found in U.S. Pat. No. 4,405,843. This switch lock includes a means for preventing disengagement of the hub legs from the barrel and also a means for biasing the plug and rotor in a desired manner.
The improved switch lock mentioned above is relatively costly to construct due to the structure necessary to accomplish the prevention of disassembly and the biasing of the plug and rotor. Furthermore, this type of switch lock may permit a degree of play between the hub and barrel as assembled which, if severe enough, could prevent the plug from rotating the rotor sufficiently enough to permit proper switching to take place within the terminal assembly.
It is therefore the object of the present invention to overcome one or more of the problems noted in prior art anti-static switch locks.